Curved Array of Light-Emitting Elements for Sweeping out an Angular Range

ABSTRACT

The present disclosure relates to curved arrays of individually addressable light-emitting elements for sweeping out angular ranges. One example device includes a curved optical element. The device may also include a curved array of individually addressable light-emitting elements arranged to emit light towards the curved optical element. A curvature of the curved array is substantially concentric to at least a portion of the circumference of the curved optical element. The curved optical element is arranged to focus light emitted from each individually addressable light-emitting element to produce a substantially linear illumination pattern at a different corresponding scan angle within an angular range. The device may further include a control system operable to sequentially activate the individually addressable light-emitting elements such that the substantially linear illumination pattern sweeps out the angular range.

BACKGROUND

A variety of techniques exist to map the geometry of an environment andobjects within the environment and/or to determine the location ofobjects of interest within the environment. These methods can includeapplying one or more patterns of illumination to the environment e..g,an array of vertical and/or horizontal lines of illumination) andimaging the environment, using one or more cameras, when exposed to suchillumination. Additionally or alternatively, a particular object withinthe environment could include a tag configured to detect the emittedillumination. The location of the tag could be determined based on thedetected illumination. In a further example, a particular object withinthe environment could include a tag configured to emit illuminationand/or to reflect illumination. The location of the tag could bedetermined by imaging the environment with one or more cameras.

SUMMARY

The specification and drawings disclose embodiments that relate to acurved array of light-emitting elements for sweeping out an angularrange. An object within the angular range, equipped with a lightdetecting device, could identify its location relative to the array oflight-emitting elements based on a time associated with a detectedillumination.

In one aspect the disclosure describes a device. The device includes acurved. optical element. The device also includes a curved array ofindividually addressable light-emitting elements arranged to emit lighttowards the curved optical element. The curvature of the curved array issubstantially concentric to at least a portion of the circumference ofthe curved optical element. The curved optical element is arranged tofocus light emitted from each individually addressable light-emittingelement to produce substantially linear illumination pattern at adifferent corresponding scan angle within an angular range. The devicefurther includes a control system operable to sequentially activate theindividually addressable light-emitting elements such that thesubstantially linear illumination pattern sweeps out the angular range.

in another aspect the disclosure describes a method. The method includesemitting light from a first individually addressable light-emittingelement toward a curved optical element. The method also includesfocusing, by the curved optical element, the light emitted from thefirst individually addressable light-emitting element to produce asubstantially linear illumination pattern at a first corresponding scanangle within an angular range. The method. further includes emittinglight from a second individually addressable light-emitting elementtoward the curved optical element. Additionally, the method includesfocusing, by the curved optical element, the light emitted from thesecond individually addressable light-emitting element to reproduce thesubstantially linear illumination pattern at a second corresponding scanangle within the angular range. The first and second individuallyaddressable light-emitting elements are in a curved array ofindividually addressable light-emitting elements. The first and secondindividually addressable light-emitting elements are sequentiallyactivated by a control system such that the substantially linearillumination pattern sweeps out at least a portion of the angular range.

In a third aspect the disclosure describes a system. The system includesa light-emitting device. The light-emitting device includes a curvedoptical element. The light-emitting device also includes a curved arrayof individually addressable light-emitting elements arranged to emitlight towards the curved optical element. A curvature of the curvedarray is substantially concentric to at least a portion of thecircumference of the curved optical element. The curved optical elementis arranged to focus light emitted from each individually addressablelight-emitting element to produce a substantially linear illuminationpattern at a different corresponding scan angle within an angular range.The light-emitting device further includes a control system operable tosequentially activate the individually addressable light-emittingelements such that the substantially linear illumination pattern sweepsout the angular range. In addition, the system includes a lightdetector. The light detector is configured to detect light emitter fromthe light-emitting device.

These as well as other aspects, advantages, and alternatives, willbecome apparent to those of ordinary skill in the art by reading thefollowing detailed description, with reference where appropriate to theaccompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of a curved array of individuallyaddressable light-emitting elements and a curved optical element,according to example embodiments.

FIG. 2 is a top view of a curved array of individually addressablelight-emitting elements and a curved optical element, according toexample embodiments.

FIG. 3 is a perspective view of a curved array of individuallyaddressable light-emitting elements projecting into an environment,according to example embodiments.

FIG. 4 is a perspective view of a curved array of individuallyaddressable light-emitting elements projecting at a light detector,according to example embodiments.

FIG. 5 is a block diagram of an example system that includes a lightemitterand an object.

FIG. 6a is a top view of light from a curved array of individuallyaddressable light-emitting elements being focused by a curved opticalelement, according to example embodiments.

FIG. 6b is a side view of light from a curved array of individuallyaddressable light-emitting elements being focused by a curved opticalelement, according to example embodiments.

FIG. 7 is a block diagram of a horizontal and vertical projector,according to example embodiments.

FIG. 8 is a flowchart of a method, according to example embodiments.

FIG. 9 is a flowchart of a method, according to example embodiments.

DETAILED DESCRIPTION

In the following detailed description, reference is made to theaccompanying figures, which form a part hereof. The illustrativeembodiments described in the detailed description, figures, and claimsare not meant to be limiting. Other embodiments may be utilized, andother changes may be made, without departing from the scope of thesubject matter presented herein. It will be readily understood that theaspects of the present disclosure, as generally described herein, andillustrated in the figures, can be arranged, substituted, combined,separated, and designed in a wide variety of different configurations,all of which are contemplated herein.

I. Overview

The location of objects in an environment can be determined byilluminating the environment with a plurality of different patterns ofillumination over time. The patterns of illumination could be specifiedsuch that different regions within the environment are exposed todifferent time-varying waveforms of light intensity. Time-varyingwaveforms of light intensity are illumination patterns (e.g., asubstantially linear illumination pattern) that are modulated in time(e.g., by a light emitter). The location of an object in the environmentcould then be determined by detecting a time-varying waveform of lightintensity received at one or more locations on the object andassociating such detected waveforms with respective regions within theenvironment. For example, a light sensor disposed on an object ofinterest could detect a time-varying waveform of light intensityincident on the object and the location of the object (e.g., a locationor angle of the object relative to one or more light emitters that areemitting different patterns of illumination over time) could then bedetermined based on the detected time-varying waveform of lightintensity.

Such a light emitter could emit different patterns of illumination thatvary across a first range of angles in a first direction relative to thelight emitter. The emitted patterns of illumination could serve toencode different regions of an environment with respect to the anglerelative to the light emitter. For example, the light emitter couldinclude an array of a plurality (e.g., thirty-two) of arranged,individually addressable light-emitting elements (e.g., light emittingdiodes—LEDs or vertical-cavity surface-emitting lasers—VCSELs) and acurved optical element (e.g., a cylindrical lens). The curved opticalelement may focus light emitted by one of the individually addressablelight-emitting elements to produce a substantially linear illuminationpattern. Further, the substantially linear illumination pattern focusedfrom each individually addressable light-emitting element could beprojected at a different corresponding angle, or corresponding range ofangles, within a first angular range. The individually addressablelight-emitting elements may thus be sequentially activated (e.g., by acontrol system) to sweep out the first angular range. The number ofindividually addressable light-emitting elements within the array couldcontribute to the width and/or resolution of the first angular range,for example. A tag or other device in the environment could detect thelight received at a particular point in the environment over time and atime-varying waveform of such detected illumination could be used todetermine the angle of the tag relative to the light emitter. Suchinformation could be used to determine the location, in one dimension ordirection, of the tag relative to the light emitter and/or relative tothe environment illuminated by the light emitter.

For example, the tag or other device that detects the light receivedfrom the light emitter could be configured to detect a synchronizationpulse from the light emitter. The synchronization pulse may be providedby illuminating all of the individually addressable light-emittingelements simultaneously, thereby illuminating the entire area within thefirst angular range. The tag could then detect when the substantiallylinear illumination pattern that corresponds to the angular position ofthe tag illuminates the tag (e.g., as the light emitter sequentiallyilluminates the environment with substantially linear illuminationpatterns). The time interval between the synchronization pulse and thecorresponding substantially linear illumination pattern could be used bythe tag to determine the relative angular position of the tag. As analternative, the individually addressable light-emitting elements couldbe activated sequentially to sweep out the angular range in a dual-scanfashion (e.g., the angular range is swept out from 0 to 90 degrees andfrom 90 to 0 degrees over the same time interval). Based on a modulationof the light emitted from the individually addressable light-emittingelements (e.g., the individually addressable light-emitting elements areactivated at a rate of 400 kHz for the increasing illumination anglesand are activated at a rate of 700 kHz for the decreasing illuminationangles), and the relative time interval between the two correspondingsubstantially linear illumination patterns, as measured by the tag, thefirst angular position relative to the light emitter can be determinedby the tag. Additionally, as the individually addressable light-emittingelements may produce Gaussian or Semi-Gaussian illumination profiles forthe substantially linear illumination patterns, the width of such aprofile, which could indicate the divergence of the illuminationpattern, could be used by the tag to determine the distance of the tagfrom the light emitter.

The light emitter could further include an additional curved opticalelement and an additional corresponding array of individuallyaddressable light-emitting elements. These additional elements could bedisposed such that the substantially linear illumination patternproduced by the additional astigmatic optical element and the additionalcorresponding array of individually addressable light-emitting elementsis substantially orthogonal to the first array of optical elements(e.g., such that the second array sweeps in a second direction that isrotated from the first direction by between 80 degrees and 100 degrees).These additional elements could thus sweep out a second angular rangethat is substantially orthogonal to the first angular range (e.g., thefirst angular range varies from left to right and the second angularrange varies from top to bottom with respect to the environment).Similarly, a tag or other device in the environment could detect thelight received from the additional array and astigmatic optical elementof the light emitter at a particular point in the environment over time.The corresponding time-varying waveform of such detected illuminationcould be used to determine the angle, relative to the light emitter inthe second direction, of the tag. Such information could be used todetermine the angular position, in a second dimension or direction, ofthe tag relative to the light emitter and/or relative to the environmentilluminated by the light emitter.

The curved optical element could include an aspheric cylindrical lens orother optical component(s). The curved optical element may be positionedrelative to the array of individually addressable light-emittingelements such that the location of a particular individually addressablelight-emitting element corresponds to a specific angle, or set ofangles, within the angular range relative to the light emitter.Alternatively, one or more of the patterns of illumination emitted fromthe light emitter (e.g., substantially linear illumination patterns) maycorrespond to a plurality of individually addressable light-emittingelements within the array.

The light emitter may be more energy efficient than other light emitterdesigns by only generating light that is used to illuminate anenvironment of interest. For example, such a light emitter design doesnot generate and discard light for non-illuminated regions of theenvironment (e.g., by discarding light to a light dump using amicromirror device). Further, such a light emitter may be relativelysmall, as it does not require masks, light dumps, or other elementsbeyond the array and curved optical element. The individuallyaddressable light-emitting elements within the array may be operated byapplying current via interconnects (e.g., on a circuit board) togenerate respective different patterns of illumination from such a lightemitter.

Multiple such light emitters may be provided, e.g., to provide differentpatterns of illumination over time such that the angle and/or locationof a tag or other light-sensitive device in an environment may bedetermined with respect to two or more angles and/or directions. Forexample, one light emitter could provide one type of illuminationpattern from a particular location that encodes regions of anenvironment in one direction. Then, another light emitter could providea different type of illumination pattern from the same location thatencodes regions of the environment in another orthogonal direction. Alight detector within the environment could detect time-varyingwaveforms of light received from the first and second light emitters anduse such detected waveforms of light to determine the angle of the lightdetector relative to the light emitter.

Additionally or alternatively, multiple light emitters could be locatedat two or more different locations. The location of a light detector inan environment, relative to the two or more different locations, couldbe determined from time-varying waveforms of light emitted by the lightemitters when detected by the light detector (e.g., usingtriangulation). A light detector receiving time-varying waveforms ofillumination from two or more light emitters could include the lightemitters emitting illumination during respective different,non-overlapping periods of time (e.g., using a method of time divisionmultiplexing), the light emitters emitting light having differentwavelengths (e.g., using a method of wavelength multiplexing), the lightemitters emitting light at different carrier frequency rates, or thelight emitters emitting light that is distinguishable, by a lightdetector, by some other method.

The array of individually addressable light-emitting elements could becurved. Further, the curved array could be disposed concentrically abouta portion of the curved optical element. In this way, the distancebetween each of the individually addressable light-emitting elements andthe curved optical element could remain constant. When compared withalternative light emitter designs, the design that incorporates acurved, concentric array of individually addressable light-emittingelements may remove focusing errors (e.g., vignetting) and allow theeffective length of the array, and correspondingly the field of view, tobe increased. The curved array of individually addressablelight-emitting elements could be assembled on the surface a flexibleprinted circuit board (PCB) sheet, for example. Alternatively, multiplelinear arrays of individually addressable light-emitting elements couldbe placed around the curved optical element and linked via directsoldering or indirect wiring to form a two-dimensionally curved array.

it should be understood that the above embodiments, and otherembodiments described herein, are provided for explanatory purposes, andare not intended to be limiting.

Example Light Emitters and Light Emitting Systems

it can be beneficial in a variety of applications to detect and/ordetermine the location of an object in an environment. Theseapplications can include tracking the location of a drone, a ball usedin a game, a conductor's baton, a controller, a body part of a person(e.g., for motion capture or gesture recognition), or some object(s). Inan example application, the location of a plurality of markers or tagsdisposed on respective different locations on a person's body could bedetermined and used to detect the location and/or motions of the personand/or of particular parts of the person's body. In another exampleapplication, the location of a control wand or other device, relative toa head-mounted device or other device worn by a person, could bedetected and used as an input to the head-mounted device or othersystem. In yet another example application, the location of a drone,robot, or other mobile system within an environment of interest (e.g., aroom of a house, a warehouse, or a factory) could be determined and usedto control the motion of the drone, robot, or other mobile system withinthe environment.

Determining the location of an object in an environment can includedetermining an absolute location of the object (e.g., relative to adefined coordinate system within the environment) and/or determining thelocation of the object relative to one or more other objects (e.g.,relative to another object whose absolute or relative location is beingdetermined, relative to a camera used to generate data used to determinethe location of the object, relative to a light emitter used toilluminate the object). Determining the location of an object couldinclude determining a location (e.g., a displacement) of the objectand/or determining an angle of the object relative to a definedcoordinate system within the environment. The angle of the object couldalso be determined relative to the location and/or orientation of someother object or device in the environment (e.g., relative to a camera,relative to a light emitter, relative to a person and/or a person's gazedirection).

The location of an object within an environment could be determined viaa variety of methods. In some examples, the location of the object couldbe determined by illuminating the object (e.g., with illumination havinga pattern of light that is specified over time and/or space) and/orreceiving light from the object (e.g., imaging the environment thatincludes the object using a camera). The object could include a tag thatis configured to emit light (e.g., a tag that is configured to emit atime-coded pattern of light to identify the tag) and/or to reflect lightfrom a light emitter to a light detector (e.g., a tag that includesretroreflective material) to facilitate optical determination of thelocation of the object. Additionally or alternatively, the object couldinclude a tag that is configured to detect light received by the object.A pattern over time of the intensity of such detected light, or someother property of the detected light, could be used to determine thelocation of the object.

Such an arrangement may include one or more light emitters illuminatingthe environment with patterns of illumination that are specified overtime and/or space such that different regions of the environment areilluminated by different patterns of illumination over time. Thus, thepattern of illumination detected over time by a light detector on anobject could be used to determine the region of the environment withinwhich the object is located. Producing such patterns of illuminationcould include scanning one or more shaped beams of light across theenvironment, providing a plurality of different patterns of light to theenvironment over time, or providing illumination to an environment insome other way. The provided illumination could vary according to anangle relative to a light emitter (e.g., an angle in one or moredirections relative to the light emitter) such that a detected intensityof the illumination over time could be used to determine the angle of alight detector (in one or more directions) relative to the lightemitter.

In a particular example, a light emitter could be configured to providea plurality of substantially linear illumination patterns duringrespective different periods of time. Each of the substantially linearillumination patterns could provide light to the environment at acorresponding angle, or corresponding set of angles, across a firstrange of angles in a first direction. Thus, as the differentsubstantially linear illumination patterns are produced by the lightemitter over time, different regions of the environment can receiverespective different time-varying patterns of intensity of the emittedillumination. As each of the substantially linear illumination patternsvaries with respect to angle in the first direction within the firstrange of angles, the time-varying patterns of illumination intensityreceived by a particular region of the environment, which is locatedwithin the first ranges of angles in the first direction relative to thelight emitter, can be used to determine the angle of the particularregion, in the first direction, relative to the light emitter.

FIG. 1 is a perspective view of a curved array of individuallyaddressable light-emitting elements 114 and a curved optical element,according to example embodiments. The individually addressablelight-emitting elements 114 may be arranged on a circuit board 110, forexample. The curved optical element may be a cylindrical lens 102 thatrefracts light emitted by the individually addressable light-emittingelements 114, in certain embodiments. Together, the cylindrical lens 102and the curved array of individually addressable light-emitting elements114 on the circuit board 110 comprise a light emitter 100.

The light emitter 100 could be configured and/or operated in a varietyof ways to produce, during respective periods of time, patterns ofillumination as described herein. In a particular example, theindividually addressable light-emitting elements 114 could be disposedon the circuit board 110 in a curved array formation (as depicted inFIG. 1). The circuit board 110 may then be disposed relative to thecylindrical lens 102 such that, when a particular individuallyaddressable light-emitting element 114, or a set of individuallyaddressable light-emitting elements 114, is operated to emit light, thelight emitter produces a respective pattern of illumination as describedherein (e.g., a substantially linear illumination pattern). Thelocation, on the circuit board 110 relative to the cylindrical lens 102,of the individually addressable light-emitting elements 114 of aparticular set of individually addressable light-emitting elements 114could be specified to control the pattern of illumination emitted by theparticular set of individually addressable light-emitting elements 114.

The duration of the periods of time during which the light emitter 100produces each substantially linear illumination pattern, and the rate atwhich a sequence of such different substantially linear illuminationpatterns is repeated, could be specified to facilitate the determinationof the angular position of a light detector or other object at more thana specified rate. For example, a sequence of substantially linearillumination patterns from the light emitter 100 could be repeated at arate greater than 10 Hertz. Further, if six or more differentsubstantially linear illumination patterns were produced during eachrepetition of such a sequence (e.g., to provide six differentilluminated environmental locations for the determination of the angularposition of the light detector or other object in the first directionrelative to the light emitter) by six different individually addressablelight-emitting elements, each pattern of illumination could be providedduring respective time periods that are less than 16.7 milliseconds induration.

The illustrated light emitter 100 for producing substantially linearillumination patterns can have a number of benefits relative to otherapparatuses for generating such patterns of illumination. The energyefficiency of generating patterns of illumination using a light emitteras described herein can be greater than other methods of generating suchpatterns of illumination (e.g., by absorbing or otherwise blocking aportion of an emitting light using a mask, by reflecting, by a digitalmicromirror device, a specified portion of light produced by a lightsource to be absorbed by a light sink or other element). Further, byforming the individually addressable light-emitting elements 114 on thecircuit board 110, an alignment between different sets of theindividually addressable light-emitting elements 114 can be preciselycontrolled. This could allow for increased alignment between features(e.g., ranges of angles) of different produced patterns of illumination(e.g., substantially linear illumination patterns) that correspond tothe respective different sets of individually addressable light-emittingelements 114. Still further, incorporating the individually addressablelight-emitting elements into a single die that is adhered to orotherwise disposed relative to a curved optical element can provide alight-emitting device that has a small size relative, for example, toother light-emitting apparatuses that include multiple masks,light-emitting elements, or other optical elements, or other means forproducing patterns of illumination as described herein. By connectingthe individually addressable light-emitting elements 114, via electricalinterconnects for example, into a number of sets of individuallyaddressable light-emitting elements 114 that correspond to respectiveemitted patterns of illumination, the different patterns of illuminationcan be produced without the use of electronic switches (e.g.,transistors) being present on the circuit board 110. Additionally, bydisposing the individually addressable light-emitting elements 114 aboutthe cylindrical lens 102 in a curved array, vignetting errors can bereduced or eliminated and the field of view can be increased as theindividually addressable light-emitting elements 114 can concentricallysurround as much as 180 degrees of the cylindrical lens 102, forexample. Additional advantages of the apparatuses for generatingpatterns of illumination described herein will be apparent.

The illustrated locations and sizes of the individually addressablelight-emitting elements 114 on the circuit board 110, the curvature andextent of the circuit board 110, and other details of the light emitter100 illustrated in FIG. 1 are intended as non-limiting, illustrativeembodiments of the methods and apparatus described herein. Differentlocations of individually addressable light-emitting elements on acircuit board, corresponding to different patterns of emittedillumination, are anticipated by the inventors. Further, differentinterconnections of sets of individually addressable light-emittingelements may be used. For example, first and second sets of individuallyaddressable light-emitting elements could be connected, with oppositepolarities, to first and second electrical pads of a circuit board. Thismay allow a selected one of the first and second sets of individuallyaddressable light-emitting elements to be operated to emit light bycontrolling a polarity of voltage provided to the sets of individuallyaddressable light-emitting elements via the first and second electricalpads. The number of electrical pads on the circuit board used to providecurrent and/or voltage to sets of individually addressablelight-emitting elements of the circuit board could be reduced by usingan electrical pad in common between a number of sets of individuallyaddressable light-emitting elements and/or pairs of sets of individuallyaddressable light-emitting elements. Other configurations ofinterconnections between individually addressable light-emittingelements and electrical pads of a circuit board may be used.

The circuit board 110 may comprise a die (e.g., a die composed ofgallium arsenide, silicon, and/or other semiconductor materials), onwhich or in which other components of the light emitter 100 are formed.In some embodiments, the circuit board 110 is a printed circuit board(PCB). Such a circuit board may have a FR-4 glass epoxy substrate withcopper conductive layers, in some embodiments. The copper conductivelayers could be etched or deposited, in various embodiments, to defineelectrical interconnects, for example. Furthermore, the electricalinterconnects may be connected to electrical pads on the circuit boardsuch that each of the sets of individually addressable light-emittingelements can be operated by providing current and/or voltage tocorresponding electrical pads on the circuit board.

In alternate embodiments, the circuit board 110 may be replaced with aflexible material. For example, organic LEDs may be formed in an organicsemiconductor substrate to define the individually addressablelight-emitting elements 114. Still further, in some alternateembodiments, the individually addressable light-emitting elements 114may be attached (e.g., physically and/or electrically) to one another todefine an array. This may obviate the need to include a structure onwhich the individually addressable light-emitting elements are arranged(e.g., the circuit board 110).

The individually addressable light-emitting elements 114 could includeLEDs, VCSELs, lasers, or other individually addressable light-emittingcomponents formed on or of the circuit board 110. For example, if thecircuit board 110 were a semiconductor material, the individuallyaddressable light-emitting elements 114 could include light-emittingdiode regions, light-emitting quantum wells, Bragg reflectors, or otherelements formed from gallium arsenide, aluminum gallium arsenide,positive or negative doping materials, or other materials or structures.Forming the individually addressable light-emitting elements 114 couldinclude photopatterning, photolithography, chemical vapor deposition,sputtering, oxidation, ion implantation, or other methods for formingelements of an integrated optoelectronic circuit.

The individually addressable light-emitting elements 114 may be packagedin such a way that a portion of the individually addressablelight-emitting elements 114 does not emit light. This could be becausethe packaging occludes some of the light-emitting area. Alternatively,there may be electrical components integrated within each individuallyaddressable light-emitting elements 114, which prevent the entireindividually addressable light-emitting element 114 from being capableof emitting light. The effective portion of the individually addressablelight-emitting element 114 may be referred to as the projecting surface,in some embodiments.

The curved optical element of a light emitter, as described herein,could be configured in a variety of ways, and include a variety ofelements (e.g., lenses, mirrors, diffraction gratings, and/or prisms)such that light emitted from a set of individually addressablelight-emitting elements of the light emitter is projected as a patternof illumination that varies with angle across a first range of angles ina first direction (e.g., that provides illumination within one or moreranges of angles within the first range of angles). This could includefocusing and/or deflecting light emitted by the individually addressablelight-emitting elements, with respect to the first direction, such thatthe location of a particular individually addressable light-emittingelement is related to a range of angles of the environment. This couldfurther include defocusing and/or spreading light from the individuallyaddressable light-emitting element with respect to a second direction.As such, the curved optical element could also be an astigmatic opticalelement.

The array of individually addressable light-emitting elements could becurved around a portion of the cylindrical lens (as illustrated in FIG.1). Such a curved array could be concentric to the cylindrical lens.Alternatively, the curvature of the curved array could be greater thanor less than the curvature of the perimeter of the cylindrical lens. Insome embodiments, the curved array could be attached to or fabricated ona section of the cylindrical lens, itself. The curved array may containmultiple rows and/or columns of individually addressable light-emittingelements that are configured to cooperatively produce one or moresubstantially linear illumination patterns by projecting light throughthe cylindrical lens. In some embodiments, the individually addressablelight-emitting elements, themselves, could be flexible. In otherembodiments, the individually addressable light-emitting elements couldbe rigid, but mounted on a flexible surface (e.g., a flexible PCB),allowing the array to be curved about the cylindrical lens.

Further, the individually addressable light-emitting elements of aninterconnected set of one or more individually addressablelight-emitting elements could be arranged in some other manner acrossthe surface of a circuit board of a light emitter. For example, theindividually addressable light-emitting elements could be distributedacross the circuit board in order to increase an amount of light emittedfrom the light emitter and/or reduce a temperature of the array ofindividually addressable light-emitting elements when the array isoperated to sequentially project substantially linear illuminationpatterns. Because the individually addressable light-emitting elementsmay be distributed across a wider area, there could be more surface areafor heat dissipation, which could thereby reduce the overall temperatureof the array of individually addressable light-emitting elements.

The distribution of individually addressable light-emitting elementsacross a circuit board in a light emitter could be provided in order toreduce an average and/or peak temperature of the light emitter when theindividually addressable light-emitting elements are being operated toemit light. This could be done by spreading the production of such wasteheat over a wider area of the circuit board or according to some otherconsideration (e.g., to simplify routing of electrical interconnectsand/or electrical pads on the circuit board, to provide a configurationof individually addressable light-emitting elements, electricalinterconnects, or other features that is compatible with circuit boardfabrication process, or to increase the amount of light output from thelight emitter).

As shown in FIGS. 1-4, the curved optical element could be a singlerefractive aspheric cylindrical lens 102. However, a curved opticalelement of a light emitter, as described herein, could includeadditional or alternative elements configured to focus, deflect, orotherwise modify light emitted from the individually addressablelight-emitting elements of the light emitter. In an example embodiment,the astigmatic optical element focuses light produced by sets of one ormore of the individually addressable light-emitting elements to produceillumination patterns such as those described herein.

To do so, such a curved optical element could include a diffractiongrating, a hologram, or some other reflective, refractive, and/orabsorptive elements. The curved optical element could include areflective element having an aspheric optical surface. The curvedoptical element could include a single lens, mirror, grating, or otheroptical element. Alternatively, the curved optical element could includemultiple optical components (e.g., multiple lenses, multiple gratings,and/or multiple mirrors).

In some examples, the curved optical element could include a singlerefractive or reflective lens having a first surface having a geometryspecified to focus and/or deflect the emitted light in a first direction(e.g., a cylindrical geometry, such as an aspheric cylindricalgeometry). Such a refractive or reflective lens could include a secondsurface having a geometry specified to defocus and/or spread the emittedlight in a second direction that is substantially orthogonal to thefirst direction (e.g., a concave geometry) such that each individuallyaddressable light-emitting element, when operated to emit light,provides light across a similar range of angles in the second direction.Such a curved optical element could therefore focus the light emittedfrom each individually addressable light-emitting element into asubstantially linear illumination pattern, for example.

Components or features of the curved optical element could be formed ona circuit board, for example, using optically transparent materials, orother elements on the surface of the circuit board (e.g., using methodsused for integrated circuit fabrication).Additionally or alternatively,the curved optical element could be bonded to the circuit board using anadhesive, clips, an armature, or some other means. This could includebonding the curved optical element (e.g., using an adhesive) to thecircuit board directly, to a package that encloses the circuit board(e.g., a ceramic, metal, or polymer integrated circuit package thatincludes a window), or to some other component of a light emitter. Alight emitter could include further optical elements in addition to thecurved optical element; for example, a plurality of microlenses could beprovided on the surface of the circuit board to focus, collimate, orotherwise modify the emission pattern of light emitted from each of theindividually addressable light-emitting elements.

As noted above, a light emitter (e.g., 100) could be operated to providea number of different patterns of illumination, during respectivedifferent periods of time, to an environment. The patterns ofillumination could be specified such that an intensity of illuminationreceived over time by an object in the environment (e.g., by a lightdetector of such an object), from the light emitter, could be used todetermine the location of the object within the environment (e.g., todetermine the angle of the object relative to the light emitter). Thiscould involve determining a pattern of light incident on the objectduring different periods of time corresponding to different illuminationpatterns. The location of the object (e.g., the angle of the objectrelative to the light emitter) could then be determined by determining aregion (e.g., a range of angles) within the environment thatcorresponds, based on the different patterns of illumination, to thepattern of received light.

Other configurations of a light emitter are anticipated by theinventors. A circuit board could include a number of sets ofinterconnected individually addressable light-emitting elements (e.g.,at least one hundred sets) such that the sets of individuallyaddressable light-emitting elements could be operated to producerespective different patterns of illumination to facilitatedetermination of the location of an object in an environment thatreceives the patterns of illumination. Such sets of one or moreindividually addressable light-emitting elements could be interconnectedwith each other and/or with electrical pads of a circuit board in avariety of ways. For example, each set of individually addressablelight-emitting elements could be connected to a respective pair ofelectrical pads of the circuit board, or a number of sets could beconnected in common to a single electrical pad (e.g., according to acommon-cathode arrangement or a common-anode arrangement). Additionallyor alternatively, pairs of sets of one or more individually addressablelight-emitting elements could share one or more electrical pads, beingconnected to such shared terminals according to an opposite polarity(that is, the anodes of the individually addressable light-emittingelements of a first set could be connected to an in-common terminalwhile the cathodes of the individually addressable light-emittingelements of a second set could be connected to the in-common terminal)such that each set of such a pair could be operated, during a respectiveperiod of time, to provide a respective pattern of illumination byproviding voltage of a corresponding polarity to the in-commonterminal(s). Other configurations of electrical pads on a light emitter,as described herein, are anticipated by the inventors.

FIG. 2 illustrates, in cross-section, the effect of a curved opticalelement (e.g., the cylindrical lens 102 illustrated in FIG. 1) of alight emitter 100 on light emitted from individually addressablelight-emitting elements 114 on a circuit board 110 of the light emitter100. Note that the dimensions, angles of emitted illumination, operationof the cylindrical lens 102 to refract light, and other aspects of FIG.2 are intended to conceptually illustrate the production of patterns ofillumination (e.g., substantially linear illumination patterns) by alight emitter as described herein and are not intended to literallyrepresent optical or other properties (e.g., angles or locations of raysof light, emission patterns of LEDs, apparent refractive indices ofoptical elements, focal lengths of refractive elements, an overalldivergent or convergent character of a refractive element and/or of alight field produced by such an element, angles of refraction of rays oflight by refractive elements) of a particular embodiment of such a lightemitter.

FIG. 2 shows a top view of a cross-section through the circuit board 110and the cylindrical lens 102 of the light emitter 100. A first set ofone or more individually addressable light-emitting elements 114 of thecircuit board 110 are projecting light toward the cylindrical lens 102,as shown. The cylindrical lens 102 is configured to focus, refract,deflect, or otherwise modify light emitted from individually addressablelight-emitting elements 114 such that a substantially linearillumination pattern is produced (e.g., at a measurement plane 202 wherea light detector may be located) by the operation of such individuallyaddressable light-emitting elements 114. The substantially linearillumination pattern may vary across an angular range according to thelocation on the circuit board 110, an emission profile, or otherproperties of the individually addressable light-emitting elements 114on the circuit board 110 and/or the location and orientation of theindividually addressable light-emitting elements 114 relative to thecylindrical lens 102. Properties of the cylindrical lens 102, theemitter 100 (e.g., an emission profile of the individually addressablelight-emitting elements 114), or other elements of the light emitter 100could be specified such that the width of the substantially linearillumination patterns intersecting the measurement plane 202 are wideror narrow, for example.

As illustrated in FIG. 2, each of the individually addressablelight-emitting elements 114 may project a pattern through thecylindrical lens 102. The patterns may be substantially linear whenprojected onto the vertical/horizontal plane at the measurement surface202 (i.e., the illumination patterns may be elongated in the verticaldimension and focused in the horizontal dimension). The individuallyaddressable light-emitting elements 114 may be arranged with respect toone another to such that the angular range can be spanned. The angularrange may span 30 degrees, 45 degrees, 60 degrees, 75 degrees, or 90degrees, when defined with respect to the light emitter 100, forexample.

As illustrated in FIG. 1, the array of individually addressablelight-emitting elements and/or the circuit board 110 on which they aremounted may be curved. The curved array can be disposed, at leastpartially, concentrically about the cylindrical lens 102, as in FIG. 2.Such a curvature can increase the span of the angular range (i.e., fieldof view) that can be illuminated by the light emitter at the measurementsurface 202 when compared with a planar array of individuallyaddressable light-emitting elements. Additionally, the curved nature ofthe array can further separate the light rays emitted by adjacentindividually addressable light-emitting elements than the light rayswould be separated with a planar array. This additional separation canlead to an increased spatial resolution at the measurement surface 202,for example. In various embodiments, the angular span of the curvedarray about the cylindrical lens could be more or less than isillustrated in the embodiment of FIG. 2. For example, the curved arraycould surround 90 degrees, 135 degrees, or 180 degrees of thecylindrical lens.

FIG. 3 is a perspective illustration of a light emitter (e..g, the lightemitter 100 illustrated in FIG. 1) sequentially projecting illuminationpatterns into an environment 302 (e.g., a room). The light emitter mayinclude a cylindrical lens 102 and a circuit board 110, withindividually addressable light-emitting elements 114 thereon (occludedfrom view), for example. The cylindrical lens 102 may focus the lightemitted by the individually addressable light-emitting elements 114 toproduce substantially linear illumination patterns at correspondingangles with respect to the light emitter 100. As the individuallyaddressable light-emitting elements 114 are sequentially activated, thesubstantially linear illumination may progress through an angular rangewith respect to the light emitter 100 (as indicated in FIG. 1 by thedashed arrows). In various embodiments, the angular range may vary inthe horizontal/depth plane or in the vertical/depth plane (e.g., if thelight emitter 100 were rotated 90 degrees in the horizontal/verticalplane). The angular range may span 15 degrees, 30 degrees, 45 degrees,60 degrees, 75 degrees, 90 degrees, 105 degrees, 120 degrees, 135degrees, 150 degrees, 165 degrees, or 180 degrees in variousembodiments. Other angular range spans are possible.

The spacing between, width, and location of the substantially linearillumination patterns illustrated in FIG. 3 are provided as an example,and are not meant to indicate a preferred embodiment. It will be readilyunderstood that multiple projection patterns are possible whensequentially illuminating the individually addressable light-emittingelements 114. In some embodiments, for example, the interstitial spacebetween adjacent substantially linear illumination patterns may besmaller than illustrated. In one such embodiment, the substantiallylinear illumination patterns may be projected conterminously to oneanother (e.g., the left edge of one of the substantially linearillumination patterns may lie immediately adjacent to the right edge ofan adjacent substantially linear illumination pattern). This may allow,if all of the individually addressable light-emitting elements wereactivated simultaneously for example, a synchronization pulse tovertically illuminate the entire portion of the environment 302 thatlies within the angular range.

Determination of the location of an object (e.g., determination of theangle of a light detector in the first direction relative to the lightemitter 100) based on time-varying patterns of illumination receivedfrom the light emitter 100 can include determining the timing ofdetection of the illumination (e.g., the timing of detection of a givenlight intensity from a plurality of measurements of the intensity oflight received by a light detector) relative to the timing of timeperiods during which each of a number of different patterns ofillumination are produced by the light emitter 100. In some examples,such timing information could be determined by the light emitter 100 anda light detector 420 both including highly accurate, synchronizedclocks. In other examples, the light emitter 100 could include a radiofrequency transmitter (or other means for wireless informationtransmission) that is operated to emit such timing information. In stillfurther examples, such timing information could be recovered from thetime-varying pattern of illumination received by a light detector fromthe light emitter 100. In some embodiments, the timing information couldbe recovered by recovering pulse timing information from changes (e.g.,rising or falling edges) in a detected time-varying illumination signal.

As illustrated in FIG. 4, the light emitter 100 may emit light into anenvironment 302 (e.g., a room) in the form of substantially linearillumination patterns (as illustrated in FIG. 3). This could beaccomplished by the light emitter 100 using a curved optical element(e.g., a cylindrical lens 102) and a series of individually addressablelight emitting elements 114 (occluded from view in FIG. 4) arranged intoan array on a circuit board. 110, for example. As the individuallyaddressable light emitting elements 114 are sequentially activated(e.g., by a control system also on the circuit board 110 connected tothe individually addressable light-emitting elements 114 usingelectrical interconnects), substantially linear illumination patternsmay illuminate different angles within an angular range defined by thelight emitter 100 in the environment 302. The sequential scanning isillustrated in FIG. 4 by the dashed arrows. Further, the locations wheresubstantially linear illumination patterns could be projected areillustrated by the solid lines emanating from the cylindrical lens 102.The substantially linear illumination pattern that is projected to theangular position of the light detector 420 is indicated in FIG. 4 byreference numeral 402.

As described above, determining the location of an object (e.g., thelight detector 402) based on a detected time-varying intensity of lightreceived from a light emitter can include making such determinationsbased on information about the timing of patterns of illuminationemitted from the light emitter. Such timing information could be basedon an internal clock of a controller of the light detector, or based ontiming information received using a receiver (e.g., timing informationtransmitted via radio frequency signals from the light emitter).Additionally or alternatively, the timing information could be presentin the timing of emission of patterns of illumination by the lightemitter. For example, the light emitter could provide illumination toall of the angular range of illumination during one or more particularperiods of time to provide synchronization timing or other data to anobject. In some examples, providing one or more of the patterns ofillumination could include modulating one or more of the providedpatterns of illumination (e.g., by varying an intensity of the providedillumination across a range of intensities and/or between a number ofdifferent discrete levels of illumination) at a specified frequency oraccording to some other pattern over time to provide timing information(e.g., to identify one or more of the patterns of illumination as a‘first’ pattern in a sequence of patterns of illumination) or to providesome other information.

Note that the detected substantially linear illumination pattern 402, asillustrated, is intended as a non-limiting example of a pattern thatcould be provided by the light emitter 100 as described herein. As analternate example, a set of patterns of illumination provided by lightemitter could vary across a first range of angles; a further pattern ofillumination could provide illumination to all of the first range ofangles. Such a pattern could be provided, as described above, to providetiming or other information to objects in the environment. Additionallyor alternatively, such a pattern of illumination could be used todetermine whether a given object is within the first range of angles andthus whether the light emitted from the light emitter can be used todetermine the location of the given object.

A number of different patterns of illumination (and corresponding numberof sets of one or more individually addressable light-emitting elementsof a light emitter) could be specified to provide determination of theangular position of an object in an environment of interest to at leasta specified resolution or accuracy. For example, ten or more differentsubstantially linear illumination patterns could be provided by a lightemitter (e.g., from ten or more corresponding sets of one or more lightemitting elements of the light emitter) during respective differentperiods of time (e.g., during a plurality of repeated respective periodsof time, according to a repeating sequence in time of producing thedifferent substantially linear illumination patterns). Each of theprovided substantially linear illumination patterns, when detected by alight detector of an object in the environment during a respectiveperiod of time, could provide a corresponding angular range in which theobject is located relative to the light emitter. The angular range inwhich the object is located may occupy a span of angles based on thewidth of the corresponding substantially linear illumination pattern. Asnoted above, the number of provided different patterns of illuminationcould be specified to facilitate determination of the angular positionof such an object to a specified degree of resolution. For example,providing ten or more different substantially linear illuminationpatterns could facilitate the determination of the angular position ofan object to a resolution of 9 degrees if the complete angular rangeswept out by the light emitter were 90 degrees. An angular resolution of9 degrees may correspond to a linear distance resolution of 15.6centimeters when such an object is within 1 meter of a light emitterthat is providing the substantially linear illumination patterns.Additionally, if the intensity profile of the substantially linearillumination patterns vary with respect to angle (e.g., due to theGaussian nature of an individually addressable light-emitting element,such as a laser), and a light detector on the object can detect thevariations in intensity, the angular resolution could be enhancedfurther.

FIG. 5 is a block diagram of a system that includes a light emitter 550that is configured to provide a plurality of different patterns ofillumination as described elsewhere herein to an environment withinwhich an object 510 is located. The object 510 includes a light detector514 and a controller 512 configured to detect illumination 520 emittedfrom the light emitter 550. The object 510 further includes atransceiver 516 configured to transmit and/or receive information toand/or from some other device (e.g., from the light emitter 550). Thelight detector 514 is configured to detect a property (e.g., anintensity) of light 520 received from the light emitter 550 (e.g., lightemitted as one or more substantially linear illumination patterns fromthe light emitter 550 during respective different periods of time). Suchlight can be detected and used to determine a location (e.g., an anglein a first direction relative to the light emitter 550) of the object510. The light emitter 550 includes a die 554, which could be disposedon a circuit board for example, that includes one or more individuallyaddressable light-emitting elements configured to provide light, via acurved optical element 556 (e.g., a cylindrical lens), to reproducerespective patterns of illumination to an environment that contains theobject 510 (e.g., substantially linear illumination patterns). The lightemitter 550 further includes a processor 552 and a memory 560 configuredto facilitate operation of the die 554 to produce such patterns ofillumination.

The light emitter 550 is configured to produce, during respectiveperiods of time, different patterns of illumination. Emitting eachdifferent pattern of illumination includes emitting illumination withinone or more ranges of angles of a first range of angles in a firstdirection relative to the device. Thus, each pattern of illuminationvaries across the first direction such that an object (e.g., 510) candetect the intensity of light received from the light emitter 550 duringsuch different periods of time and use the detected light intensities todetermine the location of the object 510 in an environment (e.g., todetermine the angle of the object 510 relative to the light emitter 550in the first direction). The light emitter 550 producing a particularpattern of illumination includes generating light from a set of one ormore interconnected individually addressable light-emitting elements(e.g., LEDs, lasers, VCSELs) of the die 554.

The processor 552 of the light emitter 550 is configured to operate thedie 554 (e.g., to apply voltages and/or currents to the different setsof one or more individually addressable light-emitting elements of thedie 554) to produce different patterns of illumination from the lightemitter 550. The processor 552 could include one or moremicrocontrollers, application-specific integrated circuits (ASICs),field-programmable gate arrays (FPGAs), or other electronic componentsconfigured to operate the die 554 to produce different patterns ofillumination during different periods of time. The processor 552 couldinclude elements configured to performs such actions using programinstructions 562 or other information contained within the memory 560(e.g., to generate a sequence of patterns of illumination according to astored pseudo-random sequence or according to some other sequence, or toindicate sonic timing information or other information by emittingillumination 520 using the die 554). Alternatively, the light emitter550 could include, instead of the processor 552 and memory 560, a numberof flip-flops, timers, multiplexers, counters, or other circuitsconfigured to operate the die 554 to produce patterns of illuminationaccording to a sequence that is statically set by the structure of suchcircuits (e.g., to provide each of a set of patterns of illumination fora specified period of time in a repeating sequence).

The memory 560 can include program instructions 562 for execution by theprocessor 552 to cause the light emitter 550 to produce differentpatterns of illumination during respective different periods of time byemitting light from respective different sets of one or moreindividually addressable light-emitting elements on the die 554 or toperform some other operations. The memory 560 may include non-volatileand/or volatile memory, in various embodiments. In some examples, theprogram instructions 562 could include instructions to provide thedifferent patterns of illumination according to a set sequence (e.g.,such that each of the different patterns of illumination are presentedrepeatedly in turn). Alternatively, the program instructions 562 couldinclude instructions to provide the different patterns of illuminationaccording to a random or pseudorandom sequence. In yet another example,the program instructions 562 could include instructions to provide asubset of the different patterns of illumination. For example, if thelocation of an object is known to a low resolution (e.g., it is knownthat the object is located within a second half of a range of angles ofinterest based on detecting light previously emitted from the lightemitter 550), only a subset of different patterns of illumination couldbe provided to facilitate determination of the location of the object toa greater resolution and/or at a higher rate over time.

In a still further example, program instructions 562 could includeinstructions to provide illumination across a range of angles ofinterest to signal some information to objects in an environment.Signaling information to objects could include indicating timinginformation about previous or subsequent patterns of illuminationemitted from the light emitter 560 or providing information about theidentity or other information about patterns of illumination emittedfrom the light emitter 550 and/or information about the order ofproduction of such patterns (e.g., a seed value or other informationabout a pseudorandom sequence of patterns of illumination).

In some examples, the light emitter 550 could include a transceiver, acommunications interface, a user interface, one or more further dies, orsome other components, and the program instructions 562 could includeinstructions to operate such further components to provide somefunctionality. For example, the light emitter 550 could include atransceiver configured to communicate with the object 510 (e.g., via thetransceiver 516 of the object 510). The program instructions 562 couldinclude instructions to operate the transceiver to transmit timinginformation, information about patterns of illumination and/or asequence of production of such patterns by the light emitter 550, orsome other information to the object 510. Additionally or alternatively,the program instructions 562 could include instructions to operate thetransceiver to receive location information determined by the controller512 of the object 510 based on light intensities detected using thelight detector 514, to transmit information about such detectedintensities such that the processor 552 can determine the location ofthe object 510 based on such detected intensities, or to receive someother information from the object 510. The program instructions 562could include instructions to operate such a transceiver to communicatewith some other systems (e.g., to transmit information about adetermined location of the object 510 to a phone, a computer, or someother system).

The light emitter 550 can be part of a smart phone, digital assistant,head-mounted display, controller for a robot or other system, or someother portable computing device. In such examples, the light emittedfrom the light emitter 550 (e.g., as different patterns of illumination)could be used to determine the location of objects (e.g., of objectsincluding light detectors) relative to such other objects (e.g., thelocation of a user's hand, on which is disposed a light detector,relative to a user's head, on which a head-mounted display including thelight emitter 550 is disposed). Alternatively, the light emitter 550 canbe part of a system that is mounted to a floor, wall, ceiling, or otherobject or building such that the location of the light emitter 550 isrelatively static relative to an environment of interest. In suchexamples, the light emitted from the light emitter 550 could be used todetermine the location of objects (e.g., of objects including lightdetectors) relative to the environment (e.g., the location of segmentsof a person's body, on which are disposed a number of respective lightdetectors, to facilitate detection of motions of the person's bodywithin the environment). Other configurations and/or applications of alight emitter as described herein are anticipated by the inventors.

The object 510 could be part of or disposed on a system a drone), a tagor other device attached to an object or person of interest (e.g., to abody segment of a person, to facilitate motion capture), or configuredin some other way to facilitate determination of the location of theobject 510 based on a time-varying intensity of light received from thelight emitter 550. This includes detecting such an intensity of lightusing the light detector 514 of the object 510. The light detector 514could include a photodiode, a phototransistor, or some other elementsthat are sensitive to light emitted from the light emitter 550 (e.g., tolight at a wavelength corresponding to the wavelength of light emittedfrom individually addressable light-emitting elements of the die 554 ofthe light emitter 550).

The controller 512 could include a variety of elements configured tooperate the light detector 514 to detect the intensity or otherproperties of light received from the light emitter 550 and/or toperform some other operations. For example, the controller 512 couldinclude logic gates, arithmetic logic units, microprocessors, registers,digital oscillators, counters, logical buses, amplifiers,analog-to-digital converters (ADCs), mixers, analog oscillators,buffers, memories, program instructions, or some other component orcomponents. The controller 512 could be configured to determine thelocation of the object 510 based on such detected illumination from thelight emitter 550 and/or to transmit, using the transceiver 516,information about the detected illumination (e.g., about the intensityof the received illumination at a plurality of points in time, about thetiming, sequence, or other information about a series of changes in theintensity of such received illumination over time) to some other system(e.g., the light emitter 550, a phone, a computer. The controller 512could be configured to perform some other operations.

The controller 512 could include a variety of components used to detectillumination from the light emitter 550 that is received by the lightdetector 514. The light detector 514 could include a photodiode, aphototransistor, a photoresistive element, or some other componentsconfigured to output a voltage, a current, or some other electricalsignal related to the intensity or other properties of the receivedlight 520. The controller 512 could include amplifiers, transimpedanceamplifiers, filters, buffers, voltage references. ADCs, or othercomponents configured to operate the light detector 514 to detect theillumination 520 received from the light emitter 550. The controller 512could include further circuitry (e.g., clock recovery circuitry todetermine relative timing information from transitions in the intensityof the detected illumination, asynchronous serial receiver circuitry todetect a sequence of changes in the intensity of the receivedillumination that are relative to the location of the object 510).

The controller 512 could be configured to detect, using the lightdetector 514, illumination from multiple light emitters and/or frommultiple different dies of a light emitter. In some examples, thecontroller 512 could include digital or analog filters configured tofacilitate detecting illumination received from multiple different lightemitters and/or from multiple different dies of a light emitter. Thiscould be done by detecting components of the illumination received bythe light detector 514 that vary at respective different frequenciescorresponding to frequencies of modulation of the illumination emittedfrom such different dies and/or different light emitters. Additionallyor alternatively, the light detector 514 could include multipledifferent light-sensitive elements (e.g., different photodiodes and/oroptical filters coupled to such photodiodes) that are sensitive toillumination at respective different wavelengths corresponding to thewavelength of illumination produced by different light emitters and/ordifferent dies of a light emitter. This could facilitate detection ofillumination received from such multiple different light emitters and/orfrom multiple different dies of a light emitter.

It is noted that the block diagram shown in FIG. 6 is described inconnection with functional modules for convenience in description.However, embodiments of the object 510 and/or the light emitter 550 canbe arranged with one or more of the functional modules (“sub-systems”)implemented in a single integrated circuit (e.g., an integrated circuitthat includes a light detector and circuitry for detecting an intensityof light received via the light detector), multiple integrated circuitsor electronic assemblies (e.g., printed circuits boards with electroniccomponents disposed thereon), or according to some other consideration.

Note that the illustrated components of the object 510 and the lightemitter 550 are intended as a non-limiting example embodiment. Also notethat light emitters configured to provide patterns of illumination to anenvironment, objects located in such an environment, and/or lightdetectors located in such an environment as described herein may includemore or fewer of the illustrated elements and/or may include furtherelements. For example, an object that is located in an environment andthat includes a light detector configured to detect light emitted from alight emitter may lack a controller or other elements configured tooperate the light detector and/or to determine the location of theobject. In such examples, the light emitter could be tethered via acable to some other system (e.g., to the light emitter 550) that isconfigured to detect the light received via the light detector and todetermine the location of the light detector. Further examples of lightemitters, light detectors, tags, and/or other objects or systemsconfigured to produce and/or detect patterns of illumination asdescribed herein are anticipated by the inventors.

As described elsewhere herein, a light emitter could include a die and acurved optical element configured to provide patterns of illuminationfrom the light emitter that vary according to angle in a specifieddirection relative to the light emitter. This could be done bygenerating light from corresponding individually addressablelight-emitting elements of the die. The location of such individuallyaddressable light-emitting elements on the die could correspond to theangle or range of angles of illumination produced from the light emitterwhen the individually addressable light-emitting elements are operatedto emit light. A light emitter configured in this way can provide suchpatterns more efficiently, in a smaller form factor, with minimalcomponents and for minimal cost, or according to some otherconsideration in a manner that is improved relative to other apparatusesor methods for producing such patterns of illumination (e..g, using adigital micromirror device to control which portions of light producedby a light source will be provided to an environment). Such a die and/orcurved optical element could be configured in a variety of ways tofacilitate production of a variety of different patterns ofillumination.

For example, while such a light emitter is described elsewhere herein asincluding a single die that is disposed relative to a curved opticalelement, multiple dies could be disposed relative to such a curvedoptical element. These multiple dies could provide respective patternsof illumination from respective sets of light-emitted elements of thedifferent dies. Such different dies could be provided to increase adegree of power dissipation from the dies, to increase a total number ofsets of individually addressable light-emitting elements on the dies andcorresponding total number of different patterns of illumination thatcan be provided by the light emitter, or to provide some otherfunctionality. This is illustrated by way of example in FIG. 7, whichshows a first die 714 and a second die 724 that each include respectivepluralities of light-emitting elements and are each set behind a firstcurved optical element 710 and a second curved optical element 720,respectively.

As described above, FIG. 6a is a top view of an array of individuallyaddressable light-emitting elements 614 arranged on a circuit board 610that project light toward a cylindrical lens 602. If sequentiallyactivated, the array of individually addressable light-emitting elements614 may repeatedly project the substantially linear illumination patternacross an angular range with respect to the light emitter (asillustrated by the arrow). The angular range swept out by the lightemitter in FIG. 6a lies in the horizontal/depth plane (axes indicated inFIG. 6a ). As indicated, the individually addressable light-emittingelements 614 are arrayed on the circuit board 610 along a curved axislying within the horizontal/depth plane. Additionally, the primary axisof the cylindrical lens 602 lies substantially parallel to the verticalaxis.

Alternatively, the same light emitter could be used to projectsubstantially linear illumination patterns that scan an angular rangethat lies in the vertical/depth plane (axes indicated in FIG. 6b ). Asillustrated in FIG. 6b , the light emitter is reoriented such that theindividually addressable light-emitting elements 664 are arrayed on thecircuit board 660 along a curved axis lying within the vertical/depthplane. Additionally, the primary axis of the cylindrical lens 652 liessubstantially parallel to the horizontal axis.

In addition, if the two emitter configurations presented in FIGS. 6a and6b were two separate emitters, they could simultaneously scan orthogonalangular ranges. Further, the two separate emitters could be placed on asingle circuit board to scan an environment, as illustrated in FIG. 7.

As discussed above, in some embodiments of a light emitter (e.g., thelight emitter 700 illustrated in FIG. 7), there may be a first curvedarray of individually addressable light-emitting elements 714 disposedbehind a first cylindrical lens 710 on the same circuit board as asecond curved array of individually addressable light-emitting elements724 disposed behind a second cylindrical lens 720. The first and secondcurved arrays could be oriented such that the curved arrays emitrespective patterns of illumination in first and second directions,respectively, such that the first and second directions are rotatedrelative to each other (e.g., such that the first and second directionsare substantially orthogonal, that is, such that the first and seconddirections differ by between 80 degrees and 100 degrees). This couldallow a light detector to determine the angle of the object relative tothe light emitter in two orthogonal directions. In another example, thetwo curved arrays of the light emitter could be located at differentlocations in the environment, and determining the location of the objectbased on the illumination received by the object from the two arrayscould include determining that the object is located on a particularplane or line within the environment based on the detected illuminationand also based on the relative locations and orientations of the twocurved arrays within the environment. Furthermore, in other embodiments,three or more curved arrays of individually addressable light-emittingelements with three or more curved optical elements could be employedacross one or more light emitters.

Illumination received by an object (e.g., by a light detector of theobject) from two (or more) different arrays and/or light emitters couldbe detected in a variety of ways. In an example embodiment, thedifferent arrays could emit patterns of illumination during differentrespective periods of time. In such an example, detecting theillumination from the two different arrays could include operating alight detector of the object to detect light received by the objectduring the different respective periods of time. In another example, thedifferent arrays could emit illumination at different respectivewavelengths and detecting the illumination from the two different arrayscould include operating multiple light detectors (e.g., light detectorscoupled to respective wavelength-selective filters corresponding to thedifferent wavelengths of the light emitted by the light emitters) of theobject to detect light incident on the object at the differentrespective wavelengths. In yet another example, the illumination emittedfrom each of the arrays could be modulated at a different respectivefrequency, and detecting the illumination from the two different lightemitters could include filtering a light intensity signal detected usinga light detector of the object at the different respective frequencies.Additional or alternative methods of detecting the intensity over timeof light received by an object from two or more arrays as describedherein are anticipated by the inventors.

Furthermore, the cylindrical lenses 710/720 and the corresponding curvedarrays of individually addressable light-emitting elements 714/724 couldbe packaged onto a circuit board 700. The circuit board 700 may includecommunication interconnects 702 for transmitting modulation signals tothe individually addressable light-emitting elements 714/724 from acontrol system 760 (e.g., a control system 760 that includes a processor762 configured to execute instructions stored on a memory 764 togenerate illumination patterns to scan an environment). The circuitboard 700 may also include power interconnects 702 that provide a supplyvoltage to the individually addressable light-emitting elements 714/724from a power supply 770. The power supply 770 may include batteries orultra-capacitors, in some embodiments. In alternate embodiments, thepower supply 770 may include a plug configured to connect to a wallsocket and an alternating current to direct current (AC to DC)converter.

III. Example Methods

FIG. 8 is a flowchart of a method 800 for operating a light emitter toproduce patterns of illumination as described elsewhere herein. Suchpatterns of illumination can be provided, during respective periods oftime, to facilitate determining the location of objects, in a firstdirection relative to the light emitter, based on illumination receivedby the objects over time from the light emitter. The patterns ofillumination are specified to spatially encode the environment of thelight emitter such that different regions of the environment (e.g.,different ranges of angles in the first direction, relative to the lightemitter) receive different time-varying patterns of illumination fromthe light emitter. Such a time-varying pattern can be detected and usedto determine which of the regions of the environment the time-varyingpattern was detected from, and thus to determine the location (e.g., theangle in the first direction) of a light detector or other apparatusused to detect the time-varying pattern with respect to the lightemitter.

The light emitter includes a number of sets of one or moreinterconnected individually addressable light-emitting elements that aredisposed in an array of the light emitter and that each correspond to arespective one of the patterns of illumination emitted from the lightemitter. The array is disposed relative to a curved optical element ofthe light emitter such that, when a particular set of one or moreinterconnected individually addressable light-emitting elements of thearray is operated to emit light, the emitted light is focused by thecurved optical element to produce a corresponding one of the patterns ofillumination from the light emitter.

At block 802, the method 800 includes emitting light from a firstindividually addressable light-emitting element toward a curved opticalelement. Block 802 could include providing a voltage difference acrossthe first individually addressable light-emitting element, in someembodiments. Further, the light emitted from the first individuallyaddressable light-emitting element could be at a corresponding intensityand/or a corresponding wavelength determined by a control system, forexample. The corresponding intensity and/or the corresponding wavelengthcould be based on a location within an environment to which the emittedlight will be directed (e.g., the emitted light directed toward thecenter of an angular range of the environment could have a greaterintensity than emitted light directed toward the edges of the angularrange).

At block 804, the method 800 includes focusing, by the curved opticalelement, the light emitted from the first individually addressablelight-emitting element to produce a substantially linear illuminationpattern at a first corresponding scan angle within an angular range.Block 804 may include focusing the light emitted by the firstindividually addressable light-emitting element in one direction (e.g.,horizontally) and spreading the light in an orthogonal direction (e.g.,vertically). In order to accomplish this, the curved optical elementcould be a cylindrical lens, in some embodiments.

The substantially linear illumination pattern may extend in onedimension (e.g., vertically) across a dimension of the environment(e.g., a wall within a room). The width of the first corresponding scanangle within the angular range may correlate to the width of aprojecting surface on the first individually addressable light-emittingelement. Alternatively, the width of the first corresponding scan anglewithin the angular range may correlate to physical characteristics ofthe light emitted by the first individually addressable light-emittingelement (e.g., beam waist of a laser beam or diffraction limit of thewavelength emitted by the first individually addressable light-emittingelement).

At block 806, the method 800 includes emitting light from a secondindividually addressable light-emitting element toward the curvedoptical element. Similar to block 802, the light emitted from the secondindividually addressable light-emitting element could be at acorresponding intensity and/or a corresponding wavelength. Thecorresponding intensity and/or corresponding wavelength may correlate toa given location within the environment toward which the light emittedby the second individually addressable light-emitting element will beprojected.

In some embodiments, the second individually addressable light-emittingelement could be disposed immediately adjacent to the first individuallyaddressable light-emitting element, within an array, for example.Furthermore, the first and the second individually addressablelight-emitting elements could both be located on a circuit board. Thefirst and the second individually addressable light-emitting elementscould further be staggered with respect to one another such that a firstprojecting surface on the first individually addressable light-emittingelement and a second projecting surface on the second individuallyaddressable light-emitting element are aligned with one another.Additionally or alternatively, the first and the second individuallyaddressable light-emitting elements could be located at differentconcentric positions about the curved optical element (e.g., both thefirst and the second individually addressable light-emitting elementscould be the same distance from the curved optical element, but disposedat different angular locations around the curved optical element).

At block 808, the method 800 includes focusing, by the curved opticalelement, the light emitted from the second individually addressable,light-emitting element to reproduce the substantially linearillumination pattern at a second corresponding scan angle within anangular range. Similar to block 804, focusing could include focusing thelight in one direction (e.g., horizontally), and spreading the light inan orthogonal direction (e.g., vertically). The reproduced substantiallylinear illumination pattern could be projected on a portion of theenvironment that lies immediately adjacent to the substantially linearillumination pattern projected by block 804, for example. This may occurif the respective first and second projecting surfaces of the first andsecond individually addressable light-emitting elements are aligned.

The method 800 could include further steps, wherein further patterns ofillumination are generated, during respective periods of time, from thelight emitter by generating light from respective further sets of one ormore interconnected individually addressable light-emitting elements ofthe light emitter. Such further patterns of illumination could beprovided to increase a resolution to which the location of a lightdetector or other object in the environment can be determined (e.g., byproviding patterns of illumination that provide illumination selectivelyto smaller portions of the environment).

Further, the method 800 could include a step providing illumination,during a particular one or more periods of time, to all of the firstrange of angles (e.g., to provide synchronization or timing informationto light detectors or other objects receiving such illumination). Themethod 800 could additionally include providing, via one or moreprovided patterns of illumination, optical transmissions of informationto light detectors in the environment. Still further, the method 800could include providing, via radio frequency transmissions, informationabout the timing, sequence, angles of an environment illuminated, orother information about patterns of illumination provided, duringrespective different periods of time, from the light emitter. The method800 could include further steps, or steps alternative to those listedhere.

FIG. 9 is a flowchart of a method 900 for illuminating an environment bya light emitter and detecting an angular position within the environmentwhere an object (e.g., a light detector) is located. The light emitterand the object could comprise a location detection system. The patternsof illumination may be specified to spatially encode the environment ofthe light emitter such that different regions of the environment (e.g.,different ranges of angles in the first direction, relative to the lightemitter) receive different time-varying patterns of illumination fromthe light emitter. Furthermore, the light emitter and the object couldcommunicate with each other in additional ways beyond the illuminationand detection of illumination patterns within the environment.

The light emitter includes a number of sets of one or moreinterconnected individually addressable light-emitting elements that aredisposed in an array of the light emitter and that each correspond to arespective one of the substantially linear illumination patterns emittedfrom the light emitter. The array is disposed relative to a curvedoptical element of the light emitter such that, when a particular set ofone or more interconnected individually addressable light-emittingelements of the array is operated to emit light, the emitted lightinteracts with the curved optical element to produce a corresponding oneof the substantially linear illumination pattern from the light emitter.

At block 902, the method 900 includes emitting a synchronizationillumination from an array. Block 902 may include illuminating aplurality of individually addressable light-emitting elements within thearray (e.g., all of the individually addressable light-emitting elementswithin the array). Further, the plurality of individually addressablelight-emitting elements within the array could emit light in a series ofpulses, modulated at a corresponding synchronization frequency,intensity, and/or pattern. The corresponding synchronization frequency,intensity, and/or pattern could be recognizable by one or more lightdetectors, for example, as a way of determining that the illuminationprovided by the individually addressable light-emitting elements in thearray in block 902 is a synchronization illumination.

At block 904, the method 900 includes detecting the synchronizationillumination using a light detector. The light detector could bedisposed at a particular angular position within an environment. Asdescribed above, the light detector could include a controller, such asa processor executing instructions stored within a memory, for example.Furthermore, the light detector could include a photodiode, aphototransistor, a photoresistive element, or some other component(s)configured to output a voltage, a current, or some other electricalsignal related to the intensity, wavelength, or other properties of thereceived light. In some embodiments of method 900. Block 904 couldinclude detecting the synchronization illumination from a plurality oflight detectors. For example, an object within the environment may havemultiple light detectors positioned at different angular positions onthe object (e.g., a light detector on the left arm and another lightdetector on the right arm of a person).

Further, detecting the synchronization illumination could includedetecting a corresponding wavelength, intensity, and/or duration ofillumination. Additionally, detecting the synchronization illuminationcould include detecting a wavelength and/or intensity profile withrespect to time. Detecting such a profile could allow the light detectorto more precisely pinpoint the angular position of the light detectorwithin the environment.

At block 906, the method 900 includes associating a synchronization timewith the detected synchronization illumination. Block 906 could includea transceiver associated with the light detector accessing a network(e.g., the public Internet) to determine the current time.Alternatively, the light detector could have an internal clock thatstores the current time. Block 906 may also include storing theassociated synchronization time in a memory. The memory could be locatedon-board the light detector, in some embodiments. Alternatively, thememory could be located remotely (e.g., a cloud storage device to whichthe light detector communicates the synchronization time).

At block 908, the method 900 includes sequentially illuminating theindividually addressable light-emitting elements in the array using acontrol system to sweep out an angular range with a substantially linearillumination pattern. In some embodiments, block 908 may includeilluminating different individually addressable light-emitting elementsfor different amounts of time. For example, the first individuallyaddressable light-emitting element in the array could be activated for500 milliseconds, and each successive individually addressablelight-emitting element could be activated for 5 fewer milliseconds,consecutively. Such an illumination scheme could allow one or more lightdetectors to detect their respective angular positions relative to thelight emitter. In addition to a modulation in time, a modulation inwavelength (e.g., each of the individually addressable light-emittingelements emits a slightly different wavelength of light) could be usedduring the sequential illumination of the individually addressablelight-emitting elements in the array.

At block 910, the method 900 includes detecting the substantially linearillumination pattern reproduced by one of the light-emitting elements inthe array using the light detector. Similarly to block 904, detectingthe substantially linear illumination pattern could include detecting acorresponding wavelength, intensity, and/or duration of illumination.Further, detecting the substantially linear illumination pattern couldinclude detecting a wavelength and/or intensity profile with respect totime. Detecting such a profile could allow the light detector to moreprecisely pinpoint the angular position of the light detector within theenvironment.

At block 912, the method 900 includes associating the detectedsubstantially linear illumination pattern with a detection time. If awavelength and/or intensity profile were detected with respect to time,block 912 could include associating the substantially linearillumination pattern with a set of detection times. Analogously to block906, block 908 could include a transceiver associated with the lightdetector accessing a network (e.g., the public Internet) to determinethe current time. Alternatively, the light detector could have aninternal clock that stores the current time. Block 908 may also includestoring the associated detection time in a memory. The memory could belocated on-board the light detector, in some embodiments. Alternatively,the memory could be located remotely (e.g., a cloud storage device towhich the light detector communicates the synchronization time).

At block 914, the method 900 includes comparing the detection time withthe synchronization time to determine the angular position of the lightdetector, using a computing device. The computing device could belocated on-board the light detector, in some embodiments. In alternateembodiments, the computing device could be a central server, forexample, that determines the angular positions of multiple lightdetectors based on multiple respective detection times andsynchronization times. The computing device, in such embodiments, maycommunicate with the light detector through a transceiver on the lightdetector, for example. Block 914 may include the computing devicesubtracting the synchronization time from the detection time todetermine a time duration between when the synchronization illuminationwas detected and when the substantially linear illumination pattern wasdetected. Further, block 914 may include the computing device dividingthe time duration between the synchronization illumination detection andthe substantially linear illumination pattern detection by anillumination time of each of the individually addressable light-emittingelements in the emitter to determine the angular position of the lightdetector. The illumination time of each of the individually addressablelight-emitting elements may have previously been transmitted from thelight emitter to the light detector. Additionally or alternatively, theillumination time may have been generated/altered based on informationcontained within the synchronization illumination (e.g., the wavelengthof the synchronization illumination serves as an indication from thelight emitter to the light detector as to the illumination time of eachof the individually addressable light-emitting elements that is used inthe corresponding illumination sequence).

The method 900 could include further steps, wherein further patterns ofillumination are generated, during respective periods of time, from thelight emitter by generating light from respective further sets of one ormore interconnected individually addressable light-emitting elements ofthe light emitter. Such further patterns of illumination could beprovided to increase a resolution to which the angular position of alight detector or other object in the environment can be determined(e.g., by providing patterns of illumination that provide illuminationselectively to smaller portions of the environment).

The method 900 could additionally include providing, via one or moreprovided patterns of illumination, optical transmissions of informationto light detectors in the environment. Still further, the method 900could include providing, via radio frequency transmissions, informationabout the timing, sequence, angles of an environment illuminated, orother information about patterns of illumination provided, duringrespective different periods of time, from the light emitter. The method900 could include further steps, or steps alternative to those listedhere.

IV. Conclusion

The particular arrangements shown in the Figures should not be viewed aslimiting. It should be understood that other embodiments may includemore or less of each element shown in a given Figure. Further, some ofthe illustrated elements may be combined or omitted. Yet further, anexemplary embodiment may include elements that are not illustrated inthe Figures.

Additionally, while various aspects and embodiments have been disclosedherein, other aspects and embodiments will be apparent to those skilledin the art. The various aspects and embodiments disclosed herein are forpurposes of illustration and are not intended to be limiting, with thetrue scope and spirit being indicated by the following claims. Otherembodiments may be utilized, and other changes may be made, withoutdeparting from the spirit or scope of the subject matter presentedherein. It will be readily understood that the aspects of the presentdisclosure, as generally described herein, and illustrated in thefigures, can be arranged, substituted, combined, separated, and designedin a wide variety of different configurations, all of which arecontemplated herein.

What is claimed is:
 1. A device comprising: a curved optical element; acurved array of individually addressable light-emitting elementsarranged to emit light towards the curved optical element, wherein acurvature of the curved array is substantially concentric to at least aportion of the circumference of the curved optical element, wherein thecurved optical element is arranged to focus light emitted from eachindividually addressable light-emitting element to produce asubstantially linear illumination pattern at a different correspondingscan angle within an angular range; and a control system operable tosequentially activate the individually addressable light-emittingelements such that the substantially linear illumination pattern sweepsout the angular range.
 2. The device of claim 1, wherein thesubstantially linear illumination pattern sweeping out the angular rangeis used to scan a physical space horizontally.
 3. The device of claim I,wherein the substantially linear illumination pattern sweeping out theangular range is used to scan a physical space vertically.
 4. The deviceof claim 1, wherein the curved array is fabricated on a curved printedcircuit board.
 5. The device of claim 1, wherein the curved arraycontains thirty-two individually addressable light-emitting elements. 6.The device of claim 1, wherein the number of individually addressablelight-emitting elements in the curved array contributes to an angularresolution of the angular range.
 7. The device of claim 1, wherein thenumber of individually addressable light-emitting elements in the curvedarray contributes to the size of the angular range.
 8. The device ofclaim 1, wherein the width of the substantially linear illuminationpattern focused from one of the individually addressable light-emittingelements is such that the substantially linear illumination patternwould at least partially overlap the substantially linear illuminationpattern focused from an adjacent individually addressable light-emittingelement.
 9. The device of claim 1, wherein the angular range is ninetydegrees, one hundred and thirty-five degrees, or one hundred and eightydegrees.
 10. The device of claim 1, wherein the curved optical elementis a cylindrical lens.
 11. The device of claim 1, wherein all of theindividually addressable light-emitting elements in the curved array aredisposed at a constant distance from the curved optical element.
 12. Thedevice of claim 1, wherein the individually addressable light-emittingelements are staggered with respect to one another in the curved arraysuch that the substantially linear illumination pattern sweeps out theangular range contiguously.
 13. A method comprising: emitting light froma first individually addressable light-emitting element toward a curvedoptical element; focusing, by the curved optical element, the lightemitted from the first individually addressable light-emitting elementto produce a substantially linear illumination pattern at a firstcorresponding scan angle within an angular range; emitting light from asecond individually addressable light-emitting element toward the curvedoptical element; and. focusing, by the curved optical element, the lightemitted from the second individually addressable light-emitting elementto reproduce the substantially linear illumination pattern at a secondcorresponding scan angle within the angular range, wherein the first andsecond individually addressable light-emitting elements are in a curvedarray of individually addressable light-emitting elements, wherein acurvature of the curved array is substantially concentric to at least aportion of the circumference of the curved optical element, and whereinthe first and second individually addressable light-emitting elementsare sequentially activated by a control system such that thesubstantially linear illumination pattern sweeps out at least a portionof the angular range.
 14. The method of claim 13, further comprising:detecting, by a light detector, the light emitted from the firstindividually addressable light-emitting element or from the secondindividually addressable light-emitting element; and associating thedetected light emitted from the first individually addressablelight-emitting element the second individually addressablelight-emitting element with a detection time.
 15. The method of claim14, further comprising: emitting, simultaneously, light from both thefirst and the second individually addressable light-emitting elements togenerate a synchronization illumination; focusing, by the curved opticalelement, the light emitted from both the first and the secondindividually addressable, light-emitting elements; detecting, by thelight detector, the synchronization illumination; associating thedetected synchronization illumination with a synchronization time; andcomparing, by a computing device, the detection time with thesynchronization time to determine an angular position of the lightdetector.
 16. The method of claim 13, further comprising: emitting,simultaneously, light from both the first and the second individuallyaddressable light-emitting elements to generate a synchronizationillumination; and focusing, by the curved optical element, the lightemitted from both the first and the second individually addressablelight-emitting elements.
 17. The method of claim 13, further comprisingmodulating, by the control system, a time interval between emittinglight from the first individually addressable light-emitting element andemitting light from the second individually addressable light-emittingelement.
 18. The method of claim 13, wherein the light emitted from thefirst individually addressable light-emitting element and the lightemitted from the second individually addressable light-emitting elementare of different wavelengths.
 19. The method of claim 13, wherein thefirst and the second individually addressable light-emitting elementsare light emitting diodes (LEDs).
 20. A system comprising: alight-emitting device, wherein the light-emitting device comprises: acurved optical element; a curved array of individually addressablelight-emitting elements arranged to emit light towards the curvedoptical element, wherein a curvature of the curved array issubstantially concentric to at least a portion of the circumference ofthe curved optical element, wherein the curved optical element isarranged to focus light emitted from each individually addressablelight-emitting element to produce a substantially linear illuminationpattern at a different corresponding scan angle within an angular range;and a control system operable to sequentially activate the individuallyaddressable light-emitting elements such that the substantially linearillumination pattern sweeps out the angular range; and a light detector,wherein the light detector is configured to detect light emitted fromthe light-emitting device.